Global dimming and brightening in the context of solar radiation

From the abstract of the lead paper by Martin Wild: Recent evidence suggests that solar radiation reaching the Earth’s surface has not been constant over time but has undergone substantial variations on decadal timescales. The available observations suggest a widespread decrease in surface solar radiation between the 1950s and 1980s (popularly referred to as “global dimming”), with some more recent evidence for a partial recovery (“brightening”).

“Global dimming and brightening” – The role of solar radiation in climate change

A special volume of the “Journal of Geophysical Research” reviews the growing research field of “global dimming” and “global brightening” in over 20 articles. These phenomena, supposedly human-induced, control solar radiation incident at the Earth’s surface and thus influence climate.

Clouds and aerosols influence the solar radiation on the earth’s surface and therefore the climate. (Photo: flickr/Schrottie)<!– (mehr Bilder) –>

Special instruments have been recording the solar radiation that reaches the Earth’s surface since 1923. However, it wasn’t until the International Geophysical Year in 1957/58 that a global measurement network began to take shape. The data thus obtained reveal that the energy provided by the sun at the Earth’s surface has undergone considerable variations over the past decades, with associated impacts on climate.

Research focus at ETH Zurich

Investigating which factors reduce or intensify solar radiation and thus cause “global dimming” or “global brightening” is still very much a nascent field of research in which especially scientists from ETH Zurich became renowned. The American Geophysical Union (AGU) has now published a special volume on the subject which presents the current state of knowledge in detail and makes a considerable contribution to climate science. “Only now, especially with the help of this volume, is research in this field really taking off”, stresses Martin Wild, senior scientist at the Institute for Atmospheric and Climate Science of ETH Zurich, who is a specialist on the subject.

Decrease in solar radiation discovered

The initial findings, which revealed that solar radiation at the Earth’s surface is not constant over time but rather varies considerably over decades, were published in the late 1980s and early 1990s for specific regions of the Earth. Atsumu Ohmura, emeritus professor at ETH Zurich, for example, discovered at the time that the amount of solar radiation over Europe decreased considerably between the 1950s and the 1980s. It wasn’t until 1998 that the first global study was conducted for larger areas, like the continents Africa, Asia, North America and Europe for instance. The results showed that on average the surface solar radiation decreased by two percent per decade between the 1950s and 1990.

In analyzing more recently compiled data, however, Wild and his team discovered that solar radiation has gradually been increasing again since 1985. In a paper published in “Science” in 2005, they coined the phrase “global brightening” to describe this new trend and to oppose to the term “global dimming” used since 2001 for the previously established decrease in solar radiation.

Only recently, an article in the journal “Nature”, which Wild was also involved in, brought additional attention to the topic of global dimming/brightening.

Air pollution favors photosynthesis

In this study, for the first time, the scientists examined the connection between global dimming/brightening and the carbon cycle. They demonstrated that more scattered light is present during periods of global dimming due to the increased aerosol- and cloud-amounts, enabling plants to absorb CO2 more efficiently than when the air is cleaner and thus clearer. According to the scientists, this is because scattered light penetrates deeper into the vegetation canopy than direct sunlight, which means the plants can use the light more effectively for photosynthesis. Consequently, there was around 10 percent more carbon stored in the terrestrial biosphere between 1960 and 1999.

The special volume, which appears in the AGU’s renowned “Journal of Geophysical Research”, provides an overview of the current state of knowledge. Almost half of the publications in the volume were either completely or partially written by ETH Zurich scientists. Wild is the guest editor, and author or co-author of ten of these articles.

The articles provide the first indication of the magnitude of these effects, how they vary in terms of time and space and what the possible consequences might be for climate change. They also discuss in detail the underlying causes and mechanisms, which are still under debate.

Many questions left open

It is particularly unclear as to whether it is the clouds or the aerosols that trigger global dimming/brightening, or even interactions between clouds and aerosols, as aerosols can influence the “brightness” and lifetime of the clouds. The investigation of these relations is complicated by the fact that insufficient – if any – observational data are available on how clouds and aerosol loadings have been changing over the past decades. The recently launched satellite measurement programs should help to close this gap for the future from space, however.

“There is still an enormous amount of research to be done as many questions are still open”, explains Wild. This includes the magnitude of the dimming and brightening effects on a global level and how greatly the effects differ between urban and rural areas, where fewer aerosols are released into the atmosphere. Another unresolved question is what happens over the oceans, as barely any measurement data are available from these areas.

A further challenge for the researchers is to incorporate the effects of global dimming/brightening more effectively in climate models, to understand their impact on climate change better. After all, studies indicate that global dimming masked the actual temperature rise – and therefore climate change – until well into the 1980s. Moreover, the studies published also show that the models used in the Intergovernmental Panel on Climate Change’s (IPCC) fourth Assessment Report do not reproduce global dimming/brightening adequately: neither the dimming nor the subsequent brightening is simulated realistically by the models. According to the scientists, this is probably due to the fact that the processes causing global dimming/brightening were not taken into account adequately and that the historical anthropogenic emissions used as model input are afflicted with considerable uncertainties.

“This is why at ETH Zurich we are working with a research version of a global climate model, which contains much more detailed aerosol and cloud microphysics and can reproduce global dimming/brightening more effectively”, says Wild. For him, the studies so far constitute “initial” estimates that need to be followed up with further research.

75 thoughts on “Global dimming and brightening in the context of solar radiation”

I have an ability to see a little more into the UV part of the spectrum than most people (I call the shade that I see “bluish white” or “ultramarine white”), and I routinely noticed that the sunlight in the end of 1990s was much harsher, and much more suffused with the UV radiation than the sunlight of my childhood years (1960s). Especially harsh “bluish white” Sun even made me worry about my eyesight in Arizona in 1998.

But who would pay attention to the observations of an obscure Russian poet? “Experts” know it all, don’t they.

OT Michael Mann was obviously stung by Christopher Booker’s comments about the hockey stick graph. The Sunday Telegraph UK has just published this letter:

The case for man-made climate change

SIR – Christopher Booker has a clear history of biased reporting on climate change, including multiple misunderstandings of the current state of the science.

He has specifically made unfounded attacks against my own research on the reconstruction of past climate variability. Mr Booker ignores the endorsement of the US National Academy of Sciences of our original findings (see “Academy Affirms Hockey Stick Graph”, Nature, Jan 29 2006) and independent research teams have subsequently extended our findings, concluding that global temperatures in recent decades are likely to have been unusual for at least the past 1,200 years.

However, the focus on the “Hockey Stick” is a distraction. Paleoclimate data provide just one of numerous lines of evidence that the significant climate changes taking place are very likely due to human-caused increases in atmospheric greenhouse gas concentrations.

For readers interested in the actual science, there are many accessible, expert sources of information, including the website RealClimate.org and recent books including my Dire Predictions: Understanding Global Warming and Climate Change: Picturing the Science by Schmidt and Wolfe.

“For readers interested in the actual science…including the website RealClimate.org…” Groan, only if you can stomach the unpleasant condescending and belittling raving of some of the nastiest ‘Internet bullies’ on-line. Reading the posts at real climate is akin to how I imagine smearing faeces all over my face would feel.

“* Professor Mann has asked us to make clear that the article did not intend to suggest any scientific wrongdoing and we are happy to do so.”

Yeh, Mann is a great scientist who is finally published by The Sun, one of the most respected scientific newspapers, a highlight in his career.
Whining about his hockey stick, attacking Christopher Booker, who’s sharp pen and objective journalism must have driven Mann into a corner with no arguments to defend his semi science lunacy.
BS (Bad Science) and personal attacks have become the trade mark of Mann.

What a reputation!

But Mann’s smear campaign against Christopher Booker does not intend any scientific wrongdoing!

Wild and his team discovered that solar radiation has gradually been increasing again since 1985

I’d like to see that data by time of day. I strongly suspect the increase is most pronounced in the early morning due to haze and clouds near the horizon at that time previously blocking sunlight.

More early morning sunlight would account for much of the increase in minimum temperatures (which occur in the early morning typically), which consitute most of the observed global warming over the last 30 years.

A quick scan at abstracts of 3 papers shows different times and trend directions (up vs down) for alleged dimming/brightening.

Also, timing seems somewhat out-of-phase with observed warming-cooling, with temperature leading rather than lagging dim-bright phases.

These are rather hasty comments – have not time to do a proper job now.

Example – Ohmura:
The record of observed global radiation begins with an increasing phase from 1920s to late 1940s/early 1960s. This brightening period (first brightening phase) is followed by the decreasing trend lasting to late 1980s, known as the global dimming, which finally translates into the second brightening phase in many regions of the world.

But global cooling extended from ~1940-1975. then warming to about 2000, then more cooling.

Long‐term variations of global solar irradiance at the Earth’s surface from the beginning of the observations to 2005 are analyzed for more than 400 sites. Further, likely causes for the variations, an estimation of the magnitudes of aerosol direct and indirect effects, and the temperature sensitivity of the climate system due to radiation changes are evaluated. The record of observed global radiation begins with an increasing phase from 1920s to late 1940s/early 1960s. This brightening period (first brightening phase) is followed by the decreasing trend lasting to late 1980s, known as the global dimming, which finally translates into the second brightening phase in many regions of the world. These decadal variations are to great extent caused by aerosol and cloud fluctuations. The total aerosol effect as well as its direct and indirect effects were evaluated mainly on the basis of the observations. To meet this goal, simultaneous observations of global solar radiation and zenith transmittance are necessary. Five such regions/sites in Europe and Japan satisfy these conditions. By using the 20‐year dimming phase from 1960 to 1980 and the 15‐year brightening phase from 1990 to 2005, it was found that the aerosol direct and indirect effects played about an equal weight in changing global solar radiation. The temperature sensitivity due to radiation change is estimated at 0.05 to 0.06 K/(W m−2). The first brightening phase lasting to 1940s/early 1960s does not show a compatibility with the variation of transmittance of the atmosphere and originated probably from a different cause.

I was going to post a similar comment. I wonder if Michael Mann’s “However, the focus on the “Hockey Stick” is a distraction. Paleoclimate data provide just one of numerous lines of evidence that the significant climate changes taking place are very likely due to human-caused increases in atmospheric greenhouse gas concentrations” represents the start of a recantation? Has he ever before admitted that the significant changes may not be caused by human-caused increases in atmospheric greenhouse gas concentration?

These series of papers are a considerable advance in understanding climate, although they also introduce even more complexity and uncertainty.

The big ramp up in temperatures in the 1990s coincided with the largest decrease in sulfur dioxide emissions and thus sulfate production. The fall of the FSU and Eastern Europe caused the very polluting factories of these regions to cease operations. In addition, the US and Europe both introduced acid rain control programs (“Two-decadal aerosol trends as a likely explanation of the global dimming/brightening transition” by Streets, D., Wu, Y., and Chin, M., 2006, Geographical Research Letters). Similarly, there has been a partial reversal, an increase since circa 2002 due to a huge increase in Chinese SO2 emissions in the last 7 or so years. As the Wild et al papers say, the regional patterns make understanding all the more difficult.

Qualitatively, the pattern of brightening in the 1990 decade, with high temperature increases, followed by flat temperatures in the post 2002 time frame, fits this pattern of SO2 emission changes. But we really don’t know how influential this pattern of SO2 emissions is on temperatures. The PDO has a temperature pattern similar to what we have seen since the 1990s, too. And to the extent that solar influences may be responsible for the lack of temperature increases in the last 2 or 3 years, and the lack of warming in the upper 700 meters of the ocean since mid-2003, that also comes into play.

How much of the temperature changes over the last half century, in the end, are due to greenhouse gases? To know that answer, we have to have a better idea of the integrated effects of these other factors, natural and man-made. And, as Roger Pielke, Sr., always reminds us, land use changes themselves affect albedo, rainfall, and rainfall patterns, all of which enter into the mix of temperatures.

Greenhouse gases increase warming. But how much? Maybe not that much…but maybe more. We are still far from knowing whether the increase might be quite modest, but we can’t rule out more problematic temperature increases completely, either.

OT: After an “unprecedently” hot August in Switzerland, last night temperatures in many parts of Switzerland fell below freezing. In a place called La Brevine (http://en.wikipedia.org/wiki/La_Br%C3%A9vine), also nicknamed “the Little Sibiria of Switzerland”, the night’s low was at -3.6°C.

“Air Pollution Favors Photosynthesis”? My suspicious genes went on alert. Since the case clearly has been made that the increase in CO2 has helped plants grow mightily, I guess the AGW/GCMers must take this one down, too, i.e., move the goal posts yet once again. Two statements really got my attention: “Only recently, an article in the journal “Nature”, which Wild was also involved in, brought additional attention to the topic of global dimming/brightening.” And “After all, studies indicate that global dimming masked the actual temperature rise – and therefore climate change – until well into the 1980s.”

I also agree with Anna V. Where is that scientifically defined term “albedo” in relationship to dimming, brightening? “Albedo is the fraction of solar energy (shortwave radiation) reflected from the Earth back into space. It is a measure of the reflectivity of the earth’s surface.” Does albedo only “go back” directly without any “scattering” among aerosols (and gases)?

They state that there are almost no measurements over the oceans. Isn’t 70% of Earth’s surface and the one that absorbs “heat” (yes, a noun) better than any other more important? If they only have land sensors, then they need to read Dr. Pielke, Sr’s paper on Land Use Land Cover.

Does GD/GB get the IPCC off the hook because they know almost nothing about clouds and therefore cannot model them in their GCMs?

Final question: Is the AGU a “real” scientific organization, or do they practice pseudo-science, too? I guess this must be another grumpy morning.

The NOVA “Global Dimming” program started with the 9/11 grounding of airplanes over the United States. The absence of contrails led to temperature changes, as measured by the difference between the daytime high and the nighttime low.
Changes over time were found by analyzing evaporation rates (with weather conditions) around the world. These were from standardized agricultural “evaporation pans”.

Discussion of albedo is verbotten in climate science (unless one is talking about the positive ice-albedo feedback).

Even though it is one of the most important variables in the climate, it has changed so little through time that it is effectively ignored (unless one is trying to account for the decline in temperatures from 1945 to 1975).

The Earth’s current albedo is 0.298 but you cannot find one single estimate for how it has varied over time. Consider ice age Earth (when ice covered one third of the land versus Cretaceous Earth (when shallow oceans covered one third of the land) (just a little primer).

OT Re: John Silver (03:30:18) :
This is not Michael Manns writing, This is Fenton Communcations writing.
—

Scientists with their own PR? Who’d have thunk it. I thought that kind of crass commercial behaviour was what evil oil did. That’s what the warmists tell us anyway. Liked the book plugs for the RC team at the end though, another Fenton product.

Closer to topic, I’d wondered what effect changes from domestic coal fires to gas/electric heating would have given the clear air effect on TSI and plant/land response to harsher, more direct light.

Veering off topic again, looks like UCLA’s solar observatory & JPL made it through the night, but demonstrates strong localised dimming-

But they’re probably better linked to Dr. Pielke’s land use, or land misuses by poor planning/zoning and fuel management. Can’t do controlled burns because that’ll harm the sacred trees, even though some of the pines need burns to seed. Come the rains, they’ve now got 8000+ hectares of changed runoff to deal with.

I read the ‘Mann’ letter as well and I’m inclined to agree that the name at the bottom my be Mann but the body of the text is quite likely Fenton.
One thing I did notice was the (partial) admission that current temperatures might be the highest “for at least 1,200 years” which does seem to suggest that at last we are dragging some sort of admission out of him that there might possibly have been a Medieval Warm Period. Of sorts. Perhaps.
Since there is more than enough historical evidence to confirm the existence of both the MWP and the LIA one wonders why there they are do resistant.
There is also enough in the way of research hypotheses (with this thread highlighting another) for any reasonable person to admit that they might just not have all the answers neatly wrapped and all tied up with a pink bow.
I don’t want them to dump all their precious theories; I’d just like them to open their minds a small bit.

John (06:25) These series of papers are a considerable advance in understanding climate, although they also introduce even more complexity and uncertainty.

Chaos-rich systems, for example climate or stock markets, invite mortals like us to proclaim that we finally understand the system based on a new model that explains its behavior over some limited time period, at some selected scale.

Then when some other mortal adds to our model or (worse for our ego) debunks it with a different and better model, we are usually tempted to defend our model and diminish the importance of others’ findings rather than thank them for their insights. Our natural human tendency is to focus on our feeble explanations rather than on the marvelous complexity and uncertainty that we are attempting to model, denying that we are inevitably doomed to be passed by a better model.

The whole AGW debate has, in my view, been sidetracked into a debate about what to do as a result of the predictions of a generation of models. We forget that all models intrinsically have fatal limits as to scale and time period. This memory lapse is convenient if it supports the agendas of some and touches on the psyche of others, which can certainly be said about the Green movement in general these days.

The latest research on solar radiation feels to me like a step towards greater understanding of reality. But I am sure that CO2 felt to many others like a step towards greater understanding of reality too, so it is not time to proclaim that the tide has turned and the latest model is finally comprehensive enough to be believed by all. As noted, typically what happens now is intense defense of previous models, not gratitude for new insights.

Just as with the stock market, climate will assert its own complexity and uncertainty, and honest people will come to regret their allegiance to a wrong model.

I have one prediction: three years from now, we will all be less confident in our beliefs about our abilities to understand complex systems. It will be a kind of “scientific agnoticism” and will be part of a societal movement away from being swept up in the expensive collective, moving instead towards individual rights and obligations. We can thank the Green movement for reminding us of our obligation to sustainability; we need not thank them for Cap & Trade.

“It is particularly unclear as to whether it is the clouds or the aerosols that trigger global dimming/brightening, or even interactions between clouds and aerosols, as aerosols can influence the “brightness” and lifetime of the clouds.”

I’m thinking this is a big problem for them. But anyway…

“Another unresolved question is what happens over the oceans, as barely any measurement data are available from these areas.”

Oh dear… They haven’t got the oceans factored in either. So much for the theory! After all, thats most of the surface of the planet, as well as a huge percentage of the atmosphere that they haven’t got a handle on yet!

“However, it wasn’t until the International Geophysical Year in 1957/58 that a global measurement network began to take shape.”

This last bit is clearly false by their own admission. Although interesting, I find this paper quite premature and speculative. Without the oceans they don’t even come close to anything that is global in scale. Without clouds they miss a large and very important chunk of the atmosphere as well. They are publishing this now for what reason again? Are we seeing scientific “rent seeking” in action?

1) NAS: according to Ian Plimer (everything you need to know about Mann is in the second chapter) it should behttp://www.nationalacademies.org/oninews/newsitem.aspx?RecordID=11676
but the link seems to be outdated
2) La Brévine is NOT high up in the Alps
3) Why do ETH not use their English name when they publish in English, which would make them S F I T Z ?

Just to clarify for those readers who may be confused, global dimming/brightening is an endogenous (Earth) source of variation. Variation in the Sun’s ability to shine on us is very tiny, very very tiny, in relation to the Earth’s ability to reflect (bounce back) the Sun’s shortwave radiation. Increased reflection means a brighter planet. Under clear sky conditions, we “look” brighter if we were standing on the moon. Under dusty, cloudy, murky conditions, we “look” dimmer if we were standing on the moon. Most of the solar shortwave radiation is absorbed but a fraction is not, it is reflected back into space (which happens at all layers of our Planet, from the outer atmosphere to the sands of Africa). In summary, this dimming and brightening refers to the Earth, not the Sun, and the paper’s focus in on the Earth, not the Sun.

I have an ability to see a little more into the UV part of the spectrum than most people (I call the shade that I see “bluish white” or “ultramarine white”), and I routinely noticed that the sunlight in the end of 1990s was much harsher, and much more suffused with the UV radiation than the sunlight of my childhood years (1960s)
Thanks for saying that. I just felt it like a more “aggresive” sunlight; in the 90’s going to the beach was really a burning experience, quite different than in the 50´s or 60´s, now it has turned to be “normal”.
Here, 12 degrees south of the equator, in el Nino 1+2 are, a thousand and more years ago, the Moche culture lived here and they made this fresco of an “Angry Sun” : http://www.giurfa.com/theangrysun.jpg

Normal everyday people report a ‘lemony-white’ Sun. Certain species of trees are badly wilted this year, even though plenty of water and cooler temps. There is a marked change in what species flourish in the shade vs direct sunlight.

“”The results showed that on average the surface solar radiation decreased by two percent per decade between the 1950s and 1990.””

But the IPCC say solar variation was only 0.1% !! Somebody is wrong

You are probably confusing solar radiation (output from the sun) and insolation (received by the earth). I’m guessing the “surface solar radiation” refers to insolation. Even if the sun’s output remains constant, the amount of sunlight received by the earth can still vary.

“and how greatly the effects differ between urban and rural areas, where fewer aerosols are released into the atmosphere”

This likely how they will explain that the UHI doesn’t increase average temperatures and the data is therefore indicative of real global temperatures. Of course, they will also have to explain how we will all be frying in the cities under 10-15 deg higher temps.

Whenever I see a photo of a tall chimney belching smoke such as the one that appears at the top of the article, I wonder how deep into the archives they had to go to find one like that. Or is it maybe current emissions from a stack somewhere in Europe where there is so much concern about AGW that, after they pay the carbon cap and tax fees, there aren’t enough funds left to fix the dirty emissions?

Reflected shortwave can bounce back to Earth, like a pingpong game played on a table in the kitchen. Clear sky reflection means that any warming/photosynthesis advantage gained by keeping more shortwave radiation, is lost. It also means that the warming affects of longwave radiation is lost as well. Meacham, Oregon regularly breaks temperature records of all sorts and is generally the coldest place in Oregon year round. It sits in a clearsky pocket at the summit of the Blue Mountains. Dry clear air, and witch tit cold. If CO2 ever becomes labeled a pollutant and some agency is in charge of pawning off captured CO2 waste, Meacham would be first in line to gladly accept the nasty stuff.

I think Christopher Booker will make mince-meat of the Mann letter in next week’s Sunday Telegraph. I’m sure Christopher will produce numerous lines of evidence to show that the significant climate changes taking place are very likely due to natural phenomena.

The new strategy from AGWers camp is to qualify anything which is opposed to their idea like pseudoscience, even when the knowledge is founded in clean science. This is called solipsism. Solipsism, as someone pointed here, is a very damaging philosophy against science which brings to disbelief every bit of the scientific knowledge accrued until the present time.

I have experienced in my flesh this kind of attacks when my argument, based on clean science, show that something from the AGW idea is wrong. I have endeavored to prove my arguments with scientific literature, and anyway, the AGWers argue that what I am managing is pseudoscience.

I have shown references like books, articles and essays written by serious scientists; however, these references have been marked like pseudoscience by AGWers. An example on this ridiculous tactic from AGWers is when someone assured that a particle that is doing work does not emit radiative energy. Another person’s argumentum was that my definition of thermodynamic system was pseudoscience, yet when I had taken the description from books on thermodynamics written by well known authors like Van Ness, Engels, Modest, Glasser, etc.

We have to be extremely careful with this innovation in the tactics of AGWers because most people don’t enjoy corroborating references written on paper and prefer to resort to links provided by those AGWers to antiscientific solipsist online articles that, ordinarily, were written by AGWers who doesn’t know the basics of physics and are creating a bogus science which fits with their beliefs.

Michael Mann, in his letter to the Sunday Telegraph, does not mention that the US Congress House Committee on Energy and Commerce (Wegman Report) made many negative comments and concluded that the Mann et al paper showed, ‘a lack of robustness and statistical flaws’. Among its findings was that, ‘it misused statistical methods which inappropriately produced hockey stick shapes in the temperature history’. The committee also said, “Dr Mann’s assessments that the decade of the 1990’s was the hottest decade of the millennium and that 1998 was the hottest year of the millennium cannot be supported by his analysis…” I also think I am right in saying that the NAS supported the Wegman Report.

His comments in the Telegraph sheds no light on anything of substance.

I’m a bit puzzled by the temperature sensitivity coefficient of 0.05C-m^2/W, mentioned in Ohmura’s abstract, versus 0.19 which one would determine from Stefan law, to estimates over 0.5 which the IPCC uses. Units are the same in all cases, and I suppose the various estimates are valid over different time spans. However, the factor of twenty seems quite surprising to me.

“His comments in the Telegraph sheds no light on anything of substance.”
No surprise there then.
It’s probably right to say that the dispute over exactly which was the warmest year of the last century is a bit of a sideshow. I’m open to correction but is it not the case that 1998 was not the warmest year in the US but might well have been globally?
Though I still cannot understand how they could tell! Or even whether it matters all that much (except, I suppose, that truth is always important.)

I collected the cutting-edge of the evidence – the story timeline, what the NAS North report said, what it was reported as saying, and what Wegman said – here. I was determined to get to the bottom of all those conflicting statements and leave a manageable checkpoint for others to check out.

Alexander Feht (01:26:32) : I have an ability to see a little more into the UV part of the spectrum than most people… and I routinely noticed that the sunlight in the end of 1990s was much harsher, and much more suffused with the UV radiation than the sunlight of my childhood years (1960s)… But who would pay attention to the observations of an obscure Russian poet? “Experts” know it all, don’t they.

Nogw (08:19:50) : Thanks [Alexander Feht] for saying that. I just felt it like a more “aggresive” sunlight; in the 90’s going to the beach was really a burning experience, quite different than in the 50´s or 60´s, now it has turned to be “normal”.

Stephen Wilde (02:29:44) : I have noticed the changes in quality of light referred to but have always regarded it as a trick of my own perceptions. Currently, in August, I am certainly aware of less power to the light than for many years past and oddly the leaves on plants and trees are deteriorating early this year. I’m not yet prepared to draw a scientific conclusion from it though.

rbateman (08:24:48) : [in reply to Stephen Wilde] Normal everyday people report a ‘lemony-white’ Sun. Certain species of trees are badly wilted this year, even though plenty of water and cooler temps.

Glad to hear these reports. I reported similar here a little while back, when I noticed the current Sun a weeny bit livelier around the time it had a few sunspots, and remembered my own perceptions from the nineties. Nobody had said anything like this, and I reckoned that many here would regard such observations as highly suspect, but I wanted to put it out anyway for the record, in case others could bear me out. It’s good to see others reporting similar perceptions.

We show that widespread brightening has occurred over the continental United States as represented by these measurements over the 12 years of the study, averaging about 8 W m−2/decade for the all‐sky shortwave and 5 W m−2/decade for the clear‐sky shortwave. This all‐sky increase is substantially greater than the 2 W m−2/decade previously reported over much more of the globe as represented by data from the Global Energy Balance Archive spanning 1986–2000 and is more than twice the magnitude of the corresponding 1986–2000 2–3 W m−2/decade increase in downwelling longwave. Our results show that changes in dry aerosols and/or direct aerosol effects alone cannot explain the observed changes in surface shortwave (SW) radiation, but it is likely that changes in cloudiness play a significant role. These SW increases are accompanied by decreasing tendencies in cloudiness, and an increasing tendency in the clear‐sky SW diffuse/direct ratio that is often associated with atmospheric turbidity.

So, variations from 1960 to the present for SW and LW are bound by +12 and -4 W/m^2; and, then comparing this to variations in temperature over the same period leads one to the conclusion that the sensitivity coefficient really is around 0.05 C-m^2/W. If provedtrue, this would make fears of runaway warming from CO2 a bit hard to gin up, yes?

About early leaf deterioration I have noticed a tiny trickle of leaves starting to fall off the trees, some trees are already seeing a decent number fall off.

Also when you look at the conditions of the bands on the right side of this site this is the first time they all said ‘poor’ at once indicating the sun’s output may still be decreasing.

This could have implications for Earth’s climate indeed, Intellicast seems to be predicting an early onset of fall-like weather here in Wichita when looking at the current forecast, the sea ice really looks like it could stay above the 2008 minimum, Intellicast showing below freezing temperatures set to return to pars of Siberia (who knows how cold it’ll get there this Winter especially if the sharp drop in temps. seen in the arctic according to one of the site links starts a trend) ect…

Lucy Skywalker (11:56:35) :Those reports are real, they worth much more credibility than adjusted satellites or next to barbacues surface stations (which are “corrected” again afterwards to avoid contradicting their “masters”).
This is why “new progressive science” says the sun has nothing to do with climate or it rains from ground to sky, and so on…

It is likely some combination of longer term solar cycles and volcanic aerosol clustering leads to periods of brightening and dimming. The 1960s after Agung had measured solar radiation declines as much as 7%.

See also this story that shows how low aerosols leads to warming just as high aerosols cooling – an intuitive result but not necessarily considered. Average conditions are somewhere in between high and low.

Pamela Gray (08:11:30) “Just to clarify for those readers who may be confused, global dimming/brightening is an endogenous (Earth) source of variation”

This reads like a suggested “consensus” Pamela. What is the benefit in pretending we know everything about solar-terrestrial relations?

I’ve noticed in recent WUWT threads that a lot of contributors are finally managing to get the social-conformity distortion-wool off their eyes — Bravo to those who do not automatically misinterpret frequent repetition as brain-numbing truth.

My poor lil brain is getting confudled by this dimming brightening stuff… Ok so dimming at the surface would make sense to me as causing cooling, but dimming by viewing from the outter atmosphere would suggest to me more short wave is being absorbed (and long wave radiated), and brightening would mean more is being reflected. Maybe the dimming is caused by the atmospheric depth scattering the short wave and… nope still makes no sense too me! Does increased GHG’s effect atmospheric depth?(im thinking humidity)

If the range of attractive force between nuclei in the core of the Sun (ro) are < 1.4 x 10^-13 cm and the kinetic energy is 10^-3 the required energy to overcome the Coulomb barrier (repulsive force between charged nuclei, protons in this case); how nuclear reactions (fusion) could take place? I mean, by means of what mechanism the nuclear reactions can take place if there is not a single nucleus in the Sun with the load of energy enough as to overcome the repulsive force?

It is not a question to resolve homework neither a loaded question; I am thinking on a possible mechanism by which the nuclear reactions in the Sun would continue happening still when the Sun switches off in this precise moment (we would not perceive any change for at least 40000 years). Perhaps, from your response I could answer MikeE’s questions.

I would be very grateful if anyone can answer my question or, at least, gives me a clue. Thanks!

Nasif Nahle 08:44 thanks for the link and invitation to visit AGU. I looked at their site and much is very general, and I would not expect geophysicists to be seduced by the AGW siren song — unless finances are involved. I must defer to the scientists to assess that one.

“Brightening” and “Dimming” simply raise my grumpy meter. I like concepts like aerosols, atmospheric gases like water vapor, “real” pollution, dust, smoke (like lots of black carbon in Los Angeles, a real health hazard), etc. The “globalness” of it all gives me the creeps, like all the AGW scams.

Pamela Gray, I guess I must be glad that I don’t live in northeast Oregon, even with your magnificently clear skies. However, at least in late spring, your country is one of the wonders of the world; the beauty is unsurpassed — the Blues, Wallowas. And looking down from a mile high at the Snake River in Hells Canyon is spectacular. Probably farming the area would be a challenge. Perhaps “she” is a white witch even though offering a cold you-know-what?

If the range of attractive force between nuclei in the core of the Sun (ro) are < 1.4 x 10^-13 cm and the kinetic energy is 10^-3 the required energy to overcome the Coulomb barrier (repulsive force between charged nuclei, protons in this case); how nuclear reactions (fusion) could take place? I mean, by means of what mechanism the nuclear reactions can take place if there is not a single nucleus in the Sun with the load of energy enough as to overcome the repulsive force? .

Quantum mechanics.

Once the distances between nuclei become of the same range as strong interactions, due to the gravitational pressure, quantum mechanics takes over. Coulomb repulsion at that distance level is orders of magnitude smaller than the strength of strong interactions ( hence the term).

The whole AGW debate has, in my view, been sidetracked into a debate about what to do as a result of the predictions of a generation of models.

That’s all it ever was in the first place.

I can’t find a copy of the first IPCC report, but from memory it concludes – The science is too uncertain as to what will happen to the climate in the future therefore we have to rely on the climate models.

“If the range of attractive force between nuclei in the core of the Sun (ro) are < 1.4 x 10^-13 cm and the kinetic energy is 10^-3 the required energy to overcome the Coulomb barrier (repulsive force between charged nuclei, protons in this case); how nuclear reactions (fusion) could take place?"

In the core of the sun the pressure and temperature are high enough that it can overcome Coulomb forces in order for nuclei to get within range of the strong force and fuse. Quantum tunnelling is associated with the wave-length of a particle which gets longer (hence can tunnel further) as you get colder, so you won't find tunnelling effects in the sun.

In Quantum Mechanics (the physics of small things) there is no certainty, only probability. So even if a particle does nor have enough energy to cross a barrier, there is a probability it will do so anyhow. Like going through a tunnel.

(The square of the absolute value of Schrödinger’s wavefunktion that describes the particle is the probability-density to find it in that spot).

Weather predictions of 85 to 90 degrees today for eastern slope of Rockies (Denver area). It was cooler than normal this morning, and very hazy from (I assume) the California wildfires. I “assume” because every time there are wildfires in California, it’s hazy – and often cooler – “downwind”.

Anyhow… it’ll be interesting to see how the predictions for mid-80’s pan out.

Very intersting. I wonder how that theory would solve the problem, although according to the theory it would be restricted to the photosphere, in any case.

Sandy (00:34:24) :

In the core of the sun the pressure and temperature are high enough that it can overcome Coulomb forces in order for nuclei to get within range of the strong force and fuse. Quantum tunnelling is associated with the wave-length of a particle which gets longer (hence can tunnel further) as you get colder, so you won’t find tunnelling effects in the sun.

I had priory thought in this solution; I mean, high pressure and temperature in the core of the Sun as possible solution. However, this solution generates more unsolvable events, like geometrical dilution and premature exhausting of protons, for example. Besides, the kinetic energy of protons in the core at high temperature and pressure lessens the nuclear cross section for nuclear reactions, so the dependence of nuclear fusion on quantum tunneling escalates, probabilistically talking.

anna v (22:34:56): and anna v (22:46:21):

Quantum mechanics.

Once the distances between nuclei become of the same range as strong interactions, due to the gravitational pressure, quantum mechanics takes over. Coulomb repulsion at that distance level is orders of magnitude smaller than the strength of strong interactions ( hence the term).

add the “tunneling effect” of quantum mechanics for the borderline cases.

In a sense there is no barrier for the strong force to overcome, except to come into range, and the gravitational pressure takes care of that.

The problem is that the kinetic energy of the protons in the core is not high enough as for protons overcome the Coulomb barrier. When one proton comes into range of another proton the repulsive force is stronger than the gravitational influence and protons’ kinetic energy doesn’t rise above the Coulomb barrier.

I think your explanation of quantum tunneling is the most feasible solution. The classical solution complicates more the problem and ends for radiating inconsistencies.

By the way, I’d like to know the total amount of protons playing in the Sun; I do remember from my school a ghostly cipher with many zeroes, but don’t remember it.

Alexej Buergin (06:15:06):

In Quantum Mechanics (the physics of small things) there is no certainty, only probability. So even if a particle does nor have enough energy to cross a barrier, there is a probability it will do so anyhow. Like going through a tunnel.

(The square of the absolute value of Schrödinger’s wavefunktion that describes the particle is the probability-density to find it in that spot).

Definitely, this is the solution; Anna and you coincide on this. Do you know what the total amount of protons in the Sun is? I don’t remember the cipher.

If my calculi run Ok, I’ll give an answer to MikeE’s question in one or two hours. Thank you friends!

I have an ability to see a little more into the UV part of the spectrum than most people (I call the shade that I see “bluish white” or “ultramarine white”), and I routinely noticed that the sunlight in the end of 1990s was much harsher, and much more suffused with the UV radiation than the sunlight of my childhood years (1960s). Especially harsh “bluish white” Sun even made me worry about my eyesight in Arizona in 1998.

But who would pay attention to the observations of an obscure Russian poet? “Experts” know it all, don’t they. “””

Optics Handbooks dealing with the sun, as an example of “natural light sources” comment on the fact that the effective color temperature of the sun (as seen from the earth’s surface) is known to vary seasonally, and also erratiucally at other intervals. Such studies date back to the 1940s and 50s when the Air Force was doing studies related to high altitude flight.

Such color temperature changes were attributed to changes (seasonal and otherwise) in the UV end of the solar spectrum; which is an area where the solar spectrum is known to deviate from a simple black body radiation curve.

They don’t mention it, but such observations can arguably be attributed to the appearance and disappearance of Ozone holes, which have a seasonal component.

In other words; ozone holes existed, long before CFCs, and caused variations in the ground level solar spectrum; long before somebody wondered about ozone holes and looked for them; which I think was somewhere around the IGY in 1957/8

No holes in the ozone layer. Really, there are not holes in the ozone layer.

The term “ozone hole” was invented by environmentalists for shaking the public up, but there are not ozone holes in the ozone layer. Perhaps slight depletions that seasonally grow and diminish in association with geomagnetic fluctuations, but no, nothing like holes in the ozone layer.

I shall elaborate a little on the effect i was kinda referring too… i dont know what the term for it is, but one easy way for short term weather prediction is how distant objects appear.. for instance, i live in the shadow of a volcano(mt taranaki) when it appears distant, its going to be fine, when it appears magnified, its going to rain. Id imagine people have used this method for thousand of years for weather prediction.(obviously in conjunction with cloud formation/wind direction/type o light at setting/rising o sun, way sound travels etc)

I hadnt given it any thought at all until i read this thread, and really have no idea on the mechanism of this phenomenon.(a quick google didnt help.. probably because im unsure on the labeling) But the atmosphere defiantly displays variable optical properties, seemingly influenced by atmospheric pressure/ or possibly humidity/ or possibly thermal disruption?(but independent of aerosols… well as far as i can tell) It indicates to me that light is scattered more, during atmospheric highs… and if it does it laterally, it seems possible that this would also be true vertically? although not necessarily.

No holes in the ozone layer. Really, there are not holes in the ozone layer.

The term “ozone hole” was invented by environmentalists for shaking the public up, but there are not ozone holes in the ozone layer. Perhaps slight depletions that seasonally grow and diminish in association with geomagnetic fluctuations, but no, nothing like holes in the ozone layer. “””

I didn’t coin the term Nasif; but “ozone holes” is the name under which this phenomenon is understood by the lay public.

I merely pointed out that there is ample evidence for the existence of whatever it is that they call “ozone holes” long before someone decided to make them headline news; and long before any possible man made cause (that’s anthropogenic in four letter words (mean word length of course)).

Well after a few days of thought, and watching my mountain as we’ve just come out of a depression into a high… ive come to the conclusion that its an air pressure caused phenomenon, basically during a high pressure, the light is traveling through more air, and getting scattered more than during a low pressure. Although humidity also seems to play a role… I know that the seasonal effect is quite noticeable, with the mountain being close to seeming half the size during a hot summer high, than during a winter low. And the variations between highs and lows being most noticeable during the summer months(thus the reason im speculating that humidity plays a role.)

But i have become quite curious about this, and would truly be thankful if one of the more enlightened posters would be able to explain what does cause this effect.

Oh and obviously the reason why this thread got me thinking about this effect, is that it seems that the dimming/brightening seems to be in counter phase to climate trends… roughly. And if higher humidity(not relative humidity) on average is expected through warming periods, and less humidity through cooling, and it effects atmospheric depth, It dosnt seem entirely impossible that this could cause a counter feed back to the current trends, irrespective if its a positive or negative trend.

As regards your mountain and weather/visibility changes I think you are commenting on a different phenomenon to the global dimming/brightening aspect.

There are old weather sayings that clearer air is less stable air (generally but not always). That is because rainfall washes particulates out whereas stable air tends to accumulate airborne particulates over time.

However I do agree that it is logical to suppose that a generally warming atmosphere might have different optical qualities to a generally cooling atmosphere. I suggested that in my earlier post on this thread.

Thanks Stephen for the response, this could certainly explain this effect. I do understand the traditional theory of global dimming with sulphates/particulates basically reflecting away more light. ( through creating a nucleus for cloud formation)

in my mind at least, it seems possible that if the atmosphere causes more scattering of the light at certain stages that it could effect the amount of light reaching the ground, but more dependent on angle of light(time o year/latitude) more so than high reflective cloud as such.

The term “ozone hole” was invented by environmentalists for shaking the public up, but there are not ozone holes in the ozone layer. Perhaps slight depletions that seasonally grow and diminish in association with geomagnetic fluctuations, but no, nothing like holes in the ozone layer. “””

I didn’t coin the term Nasif; but “ozone holes” is the name under which this phenomenon is understood by the lay public.

I merely pointed out that there is ample evidence for the existence of whatever it is that they call “ozone holes” long before someone decided to make them headline news; and long before any possible man made cause (that’s anthropogenic in four letter words (mean word length of course)).